The commonly held theory is that when a person looks up to their right, they’re lying. If they look up to their left, they’re said to be telling the truth.

But in three separate experiments testing that theory, researchers from Edinburgh University and Hertfordshire University found no connection between eye movements and whether people were being truthful. “This is in line with findings from a considerable amount of previous work showing that facial clues (including eye movements) are poor indicators of deception,” wrote the authors of the study published in the journal PLoS ONE.

The authors attribute the popular wisdom about “lying eyes” to claims made by practitioners of neuro-linguistic programming (NLP). The therapy method, which attempts to improve people’s communication skills by teaching them about eye-movements and thought, says that when people look up to their right they are visualizing a “constructed” event, and when they look to the left, they’re visualizing an actual “remembered” memory.

The notion that “constructed” means “lie” became popular, despite the fact that there’s little scientific evidence to back up the claim.

In the first experiment, the researchers videotaped 32 right-handed participants as they either lied or told the truth. (The NLP theory pertains to right-handed people, so left-handed folks were excluded from the study.) Then the researchers carefully analyzed the volunteers’ eye movements, and found that they were equally likely to glance upward and to the right or upward and to the left, regardless of the truthfulness of their statements.

In the second experiment, researchers recruited 50 participants and randomly educated half of them about the NLP lying-eye trick. Then the participants watched the videos of the 32 people from the previous experiment and were asked to indicate whether they thought each person was lying or telling the truth, and how confident they were in their assessment. Result: there was no difference in accuracy of lie detection between the 25 participants who were told about the eye-movement theory and those who weren’t.

In the third experiment, the researchers watched videos of 52 people publicly appealing for help in finding their relatives who had gone missing. the videos were gathered from news agencies in several countries, including Australia, Canada, Britain and the U.S. In half cases, the family members were known to be lying; in the other half, they were telling the truth. The researchers monitored and coded their eye movements, counting the number of times people either looked up and to the right or up and to the left. There was no link between eye movements and whether or not the people were telling the truth.

That’s not to say that eye movements have nothing to do with what a person is thinking. In an interview with ABC News, Howard Ehrlichman, a professor emeritus of psychology at Queens College of the City University of New York, who has done considerable research on the topic, said: “I found that while the direction of eye movements wasn’t related to anything, whether people actually made eye movements or not was related to aspects of things going on in their mind.”

He noted that people tend to move their eyes, about once per second on average, when they are retrieving information from their long-term memory. “If there’s no eye movement during a television interview, I’m convinced that the person has rehearsed or repeated what they are going to say many times and don’t have to search for the answer in their long-term memories,” he told ABC News.

Ehrlichman also confirmed that none of his research connected the direction of eye movements to lying.

The NLP, for its part, maintains that its teachings about eye movements were never specifically meant to be applied to lie detection. Rather, eye movements indicate how a person is processing information — whether it’s visual, auditory or physical information, or whether it’s remembered or created, said Steven Leeds, a co-director of the NLP Training Center of New York.